Multimedia synchronization system

• US 5,553,222 A
• Filed: 12/19/1995
• Issued: 09/03/1996
• Est. Priority Date: 05/10/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Taligent, Inc. (HP Inc.)
• Inventors: Edelman, Bradley A., Tobias, John C. II, Dilts, Michael R., Denman, Matthew L., Milne, Steve H., Tindell, James M.
• Primary Examiner(s): Zimmerman, Mark K.
• Assistant Examiner(s): Feild, Joseph H.
• Application Number:
  US08/575,002
• Time in Patent Office: 259 Days
• Field of Search: 395/154, 395/550, 395/155, 395/159, 395/161, 369/19-20
• US Class Current: 715/201
• CPC Class Codes: G06F 16/40 of multimedia data, e.g. slideshows comprising image and additional audio data retrieval of still image data G06F16/50; retrieval of audio data G06F16/60; retrieval of video data G06F16/70
• CPC Class Codes: H04N 21/23412 for generating or manipulating the scene composition of objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/44012 involving rendering scenes according to scene graphs, e.g. MPEG-4 scene graphs
• CPC Class Codes: Y10S 715/967 Visual or iconic programming

Abstract

A method and system for providing synchronization of the timing of various multimedia events. Clock objects are defined in the storage and associated with an internal or external source of current time. The clock objects are able to be displayed on the display, but can be hidden once their linkages are defined. One or more multimedia objects representative of audio, visual or other multimedia events are defined and linked to a particular clock object or clock objects. Then, a processor synchronizes the multimedia objects with the associated clock object or objects. Finally, the various multimedia events are performed in synchronization with their associated clocks.

Claims

1. A computer system for synchronizing presentation of a time-based media sequence in response to a synchronization request specifying a new clock rate of presentation of the time-based media sequence the system comprising:

(a) a storage;

(b) means for providing a master time signal;

(c) a clock object for providing a current time value, the clock object residing in the storage and including

current time means for computing the current time value according to a clock function of the master time signal, an original clock rate value, and an original offset value,

(d) meadia sequence presentation means, cooperating with the clock object, for presenting the time-based meadia sequence in synchronism with the current time value; and

(e) clock synchronization means, responsive to the synchronization request, for synchronizing the clock object so that the presentation means may present the media sequence at the new clock rate while keeping the current time value unchanged at the instant of synchronization, the clock synchronization means including;

means for computing a new offset value according to a new clock function of the master time signal, the new clock rate, the original clock rate value, and the original offset value and

means for replacing the original clock rate values and the original clock offset value of the clock object with the new clock rate and the new offset value, respectively.

2. The system as recited in claim 1, including a display, means for displaying an icon graphic on the display, means for detecting a user manipulation of the icon graphic and means responsive to the user manipulation of the icon graphic for generating the synchronization request.

3. The system as recited in claim 2, wherein the clock object includes means for generating a first clock icon on the display representative of the clock object, and wherein the system further comprises a second clock object including means for displaying a second clock icon on the display representative of the second clock object, and means for linking the clock object to the second clock object via a geometric figure joining the first clock icon to the second clock icon on the display so that the current time attribute of the clock object is provided as a master time signal to the second clock object in order to synchronize the second clock object to the clock object.

4. The computer system as recited in claim 1 wherein the means for providing a master time signal, comprises a second clock object having means for computing a second current time value resident in the storage wherein the second current time value is provided as the master time signal.

5. The computer system as recited in claim 1 further comprising means for receiving a new offset signal and for replacing the original offset value with the new offset signal to cause the current time means to compute a new current time value according to the clock function.

6. The computer system as recited in claim 1 wherein the clock function computes the current time value as the sum of an offset values and a multiplicative product of a rate value and a master time signal value.

7. A method of synchronizing presentation of a time-based media sequence in response to a synchronization request specifying a new clock rate of presentation of the time-based media sequence on a computer having a storage and a display and a mechanism for providing a master time signal, the method comprising the steps of:

(a) creating a clock object in the storage and including a mechanism for computing a current time value according to a clock function of the master time signal, an original clock rate value, and an original offset value

(b) presenting the time-based media sequence in synchronism with the current-time value;

(c) in response to the synchronization request, computing a new offset value according to a new clock function of the master time signal, the new clock rate, the original clock rate, and the original offset value;

(d) replacing the original clock rate value and the original clock offset value of the clock object with the new clock rate and the new offset value respectively, so that the media sequence may be presented at the new clock rate while keeping the current time value unchanged at the instant of synchronization.

8. The method as recited in claim 7, the method further comprises the steps of:

(e) displaying an icon graphic on the display;

(f) detecting a user manipulation of the icon graphic; and

(g) generating the synchronization request in response to the user manipulation of the icon graphic.

9. The method as recited in claim 7, wherein the clock object created in step (a) includes means for generating a first clock icon on the display representative of the clock object, and wherein the method further comprises the steps of:

(h) creating a second clock object including means for displaying a second clock icon on the display representative of the second clock object;

(i) linking the clock object to the second clock object via a geometric figure joining the clock icon to the second clock icon on the display so that the current time attribute of the clock object is provided as a master time signal to the second clock object in order to synchronize the second clock object to the clock object.

10. The method as recited in claim 7 further comprising the steps of:

(j) creating a second clock object having a mechanism for computing a second current time value resident in the storage; and

(k) providing the second current time value to the clock object as the master time signal.

11. The method as recited in claim 7 further comprising the steps of:

(l) receiving a new offset signal; and

(m) replacing the original offset value in the clock object with the new offset signal to cause the mechanism for computing the current time value to compute a new current time value.

12. The method as recited in claim 7 wherein step (a) comprises the step of:

(a1) creating a clock object with the clock function which computes the current time value as the sum of an offset value and a multiplicative product of a rate value and a master time signal value.

13. In a computer system having a storage and multimedia presentation object in the storage for presenting multimedia data in synchronism with a current time value provided to the presentation object, a synchronization framework residing in the storage for controlling time relationships in a multimedia application, which includes the multimedia presentation object and which operating on the computer system, the synchronization framework comprising:

(a) in the storage, data defining a time source class having a master time value attribute for storing master time signal value and a get member function for retrieving the master time signal value and storing the master time signal value in the master time value attribute;

(b) in the storage, data defining an application-subclassable clock class having

a current time attribute,

an offset value attribute,

a rate value attribute,

a member function for calculating the current time attribute of a clock object as a clock function of a master time signal value, the rate value attribute, end the offset value attribute of the clock object,

a member function for providing the current time value to a multimedia presentation object to control presentation of multimedia data, and a member function, responsive to a synchronization request accompanied by a new clock rate, for computing a new offset value according to a new clock function of the master time signal, the rate value, the offset value, and the new clock rate, so that the presentation object may present the multimedia data at the new clock rate while keeping the current time value of the clock object unchanged at the instant of synchronization.